Telephone system



F. LILL TELEPHONE SYSTEM Dec. 5, 1933.

Filed May 2, 1932 In1.rin or Frisdriczh Lin tit Patented Dec. 5, 1933 TELEPHONE SYSTEM Friedrich Lill, Vienna, Austria; assig'nor to Siemens & Halske Aktiengesellschaft, Siemensstadt, near Berlin, Germany 5 Application 'May 2, 1932, Serial No. 608,611,

and in Austria May 21,1931

6 Claims ..(c1.'179-2v) The present invention relates to a Circuit arrangement for automatic telephone systems in which connections of high as well as low value are set up over the same connecting devices.

In arrangements oi this type, known heretofore, the release of the connecting devices, seized for a connection of high value, depends entirely on the station having setup the high valued connection. The result of this is that if 2. called subscriber hasnot replaced his receiver at the end of the high valued connection, other connecting devices of importance for the traffic are unnecessarily engaged. This causes undue delays in the setting up of a further call of high value if such a call isto be put through immediately after the end of a preceding'high valued connection.

The present invention eliminates these defects by providing the connecting devices with switching means which, without releasing said connecting devices over which the line is seized remove the line guarding against connections of high value, when a subscriber or operator setting up a connection of this type releases a high valued connection.

In comparison to prior arrangements the present invention also provides important advantages particularly with regard to the circuits and service inasmuch as, on the one hand, one single relay is used for carrying out all .the special switching operations necessary for the setting up of a connection of high value in the connecting devices and, on the other hand, special switching operations to be performed, at an operators position, when completing connections of high value are carried out by actuating one and the same switchingmeans. This is achieved by all the special switching'operations required for the setting up of a connection of high value being initiated by applying the same potential to one and the same wire of the speaking leads.

The accompanying drawing shows an embodiment of the invention: Connections of high value constitute toll connections extending, for example, from a toll exchange FA to an automatic exchange, for example, exchange B. Connections of low value constitute local connections set up, for example between the two subscribers Tn and T121 connected to the same exchange B. The connecting devices in exchange B comprise a preselector VW, a first group selector IGW and a final selector LW adapted to operate for local as well as toll connections.

The setting up of. a toll connection for the subscriber Tn of the exchange B received in the toll exchange FA will now be described. The

operatorat the toll position FP who is to complete the connection inserts the plug St in the jack Kl after having received the call number of the required subscriberTnirom thedistant subscriber... The insertion of the plug in the jack causesrelay C of the repeater Ue to be energized. Relay C closes its contact .260 and thereby seizes thetoll group selector FGWI. Relay C1 in this. toll groupselectcr is then energized; Relay C1 closes its contact 4201; and thus prepares. the test circuit to the final selector LWZ. The operator at the toll position FP now commences to dial. This causes the impulse contactnsi to apply earth intermittently to the a-lead so that relay A of the repeater Us is energized accordingly in the following circuit: earth, contact nsz', plug 'St, K1, a-lead,:upper primary winding of the repeater Ue, winding of relay A, battery, earth." Relay A is energized and over its contact 4a transmits impulses to the impulse receivingrelay A1 of the toll group selector FGWl.',This circuit extends as .follows: earth,

contact 4a, rotary off-normal contact 441.011 windingof relay A1, battery, earth. The toll group selector FGWl is set to an. idle junction' closing its contacts 40111 and41p1 and by shortcircuiting its high resistance winding I by means of contactv 43121, guards the seizedline in known manner against further seizures. The circuit for the settingof the toll groupselector EGWI is of no importance for the invention and, therefore, have not been shown. Relay C2 in "the final selector LW2 is energized and prepares its own 5 locking circuit by closing its contact,66c2. On the receipt of the first impulse; relay Vg in the repeater Ue is, energized in the following circuit: earth contacts 180, 12a, winding II of I relay V, battery, earth. Relay V being con structed as. a slow-acting relay is maintained energized during the impulse series. The upper primary winding of the repeater Ue isshortcircuited on the energization of relay V due .to the closing of contact Zuso as to improve the impulse transmission" and for the same reason 33h, winding I of relay V, battery, earth.

- relay S after the end of the impulse.

the secondary winding of the repeater is opened by means of contact 312.

When the toll group selector FGWl has been duly set to an idle final selector in exchange B, for example, the shown final selector LW2, relay S in the repeater Ue is energized in the following circuit: earth, winding I of relay B2, contact 61y, junction line VL, b-wiper of the toll group selector, contact 41121, secondary winding of the repeater Ue, contact 291:, winding of relay S, battery, earth. Relay B2 in the final selector LW2 is not energized in this circuit. Relay S selector LW2 is intermittently energized and deprepares a circuit for relay U by closing its contact 11s. The impulse series for the setting of the final selector LW2 is now transmitted. This causes relay A2 in the final selector LW2 to be energized over: earth, contacts'4a, 40111, a-wiper of the toll group selector FGWI, junction line VL, contact 501 2, winding I of relay A2, battery, earth. Relay U in the repeaterUe is energized in the following circuit afterthe first impulse: earth, contacts 180, 14v, 13v, 113, 9y, 6h, winding of relay U, battery, earth. Relay U is maintained energized over its contact l'lu when relay S is disconnected from the b-lead, during the impulse series due to the energization of relay V. Relay V is released at the end of this impulse series and is followed by the slow-acting.

relay U. The following circuit for relay H is completed during the release period of relay U: earth, contacts 180, 15v, 19a, 16y, winding of relay H, battery, earth. Relay H is maintained energized over its contact 2011.. Due to the energization of relay H a potential is'mornentarily applied to the b-lead which causes relay V in the repeater Ue2 and relay B2 in the final selector LW2 to be energized. The energization of relay B2 in the final selector LW2causes the final selector LW2 to be changed over for toll traffic. The circuit extends as follows when the potential is applied: earth, winding I of relay B2, contact 61y, junction line VL, b-wiper of the toll selector FGWI', contact 41331, lower secondary winding of therepeater Ue, contacts'31u, Re lay V in the repeater Ue opens its contact 291) so that relay B2 in the final selector LW2 cannot be maintained energized over the winding of The release of relay U ends theimpulse transmission. This release is initiated by the opening of contact 6h. Relay V is also then released and by closing its contact 2912 connects relay S again to the b -lead causing-this relay to be re-energized.

On the intermittentenergization and deenergization of relay A2 in the final selector LW2, the following circuit for the vertical magnet Hm of the final selector LW2 is set up during the impulse transmission: earth, contact 109a2, winding I of relay V2, contact 110 u2, rotary offnormal contact 79102, winding of the vertical magnet Hm, battery, earth. Relay V2 is also energized in this circuit. It remains energized during the impulse series in the manner of a slow-acting relay. The final selector LW2 raises its switchwipers to the required level. Relay V2 is released at the end of the impulse series. The foHowing circuit is closed for relay U2: earth, ofif-normal contact 108k2, contacts 107122, 10402, winding I of relay U2, rotary off-normal contact I9w2, winding II ofthe vertical magnet Hm, battery, earth. The vertical magnet Hm is not energized in this circuit but relay U2, on the other hand, closes its contact u2 and thereby the release of relay B2:

prepares the circuit for the rotary magnet Dm. In addition, due to the fact that relay B2 is energized by the changing over impulse, transmitted over the b-lead after this impulse series, the following circuit for relay F2 is set up: earth, contacts 9503, 92113, 91122, a2, 8312, 97b2, winding I .of'relay F2, battery, earth. Relay F2 remains energized in the following circuit after earth, contacts 9603, 93173, 90122, 88f2, winding I of relay F2, battery, earth.

The impulse receiving relay A2 of the final energized on the succeeding impulse series and thereby sets up the following circuit for the rotary magnet of the final selector: earth, contact 109a2, winding I of relay V2, contact 80u2, 101112, winding of the rotary magnet Dm, battery, earth. The rotary magnet Dm and relay V2 are energized in this circuit. The switch Wipers of the final selector LW2 are set to the required subscribers line according to the impulses transmitted. Due to relay V2 being reenergized in the above circuit the circuit for winding I of relay U2 is cut off due to the opening of contact 10702. Relay U2, however, remains energized in the following circuit during the impulse series: earth, contacts 9503, 92103, 98172, 88]2, '87f2, 8602, 83u2, 82u2, 8112, 75172, winding II of relay U2, battery, earth. Relay V2 is first deenergized at the end of this impulse series and is followed by relay U2. Relay P2 is unable to carry out the testing operation due to the fact that the test circuit, closed in the local traflic, is cut off by the opening of contact 89 2. In order to initiate the testing the operator at the toll position FP depresses the key FT and thus applies a potential to the b-lead. Relay B in the repeater Ue is then energized in the following circuit: earth, battery, key FT, plug St, jack K1, b-lead, lower primary winding of the repeater Ue, winding of relay B, contacts 34y, 35s, earth. It should be noted that at the beginning of the second impulse series for the setting of a final selector LW2, relay Y in the repeater Ue was energizedin the following circuit: earth, contacts 18c, 14v, 1312, 11s, 91/, 7h, 10a, winding I of relay Y, battery, earth.

Relay V is placed in the following locking circuit: earth, contacts 180, 21y, winding II of relay Y, battery, earth. Relay B, when energized, closes its contact 281) and thereby sets up the following'circuit for relay B2 in the final selector LW2: earth, battery, contact 28b2, lower seccndary winding of the repeater Ue, b-lead, contact 41121, b-wiper of the toll group selector FGW, junction line VL, contact 61y, winding I of relay B2, earth. Relay B2 in the final selector LW2 is energized and closes the following circuit for relay P3: earth, contacts 119122, l20b2, 7M2, Winding I of relay P3, contacts 98b2, 97b2, winding I of. relay F2, battery, earth. Relay P3 is energized if the subscribers line is idle or seized for a local call and is placed in the following locking circuit: earth, contacts 9503, 93333, 94293, winding II of relay P3, rotary on?- normal contact 78w2, winding of vertical magnet Hm, battery, earth. The vertical magnet Hm is not energized in this circuit.

If the subscribers line is seized for a toll call, relay P3 is unable to respond due to the fact that direct earth is applied to the c-lead and relay P3 is consequently short circuited over contacts 69332, ll 2, 72f2 of the other final selector set to the line of the subscriber Tn in the manner described below; The operator at the toll position FP, in such a case, receives the busy signal over: earth, winding of transformer Bee, condenser Cp, rotary off-normalcontactl2lw2, contact 122 72, winding II of relay A2, winding II of relay B2, contacts 84u2, 84112, 91b2, 92b3, 9503, earth. The busy signal is inductively transmitted to winding I of relays A2 and B2 and thence to the toll operators position FP.

It will first. be assumed that the required subscribers line Tn is idle. In such a case relay P3 is energized and maintained in this condition in the manner described above. Relay V2 is energized over: earth winding IIof relay V2, contact 112123, battery, earth. This relay opens its contact 11402, and thereby breaks the automatic call signal provided for local traffic over the time switch SS and Winding I of relay R2. The locking circuit for Winding I of relay F2 is cut off by the opening of contact 92;)3. Relay F2 which was maintained energized .over winding I of relay P3 while the key FT was depressed is energized as soon as the key F1 is released. A test circuit for relay P2 is prepared by the closing of contact 92103. The required subscribers line being idle, .relay P2 is immediately energized in the following circuit: earth, contacts 95c3, 93 3, windings II and I of relay P2, c-Wiper of the final selector LW 2, battery, earth in the preselector of the subscriber Tn. Its contacts 58302 and 571:2 switch throughto the two speaking leads. The high resistance winding II of relay P2 is short-circuited when contact 69322 is closed and the seized line is guarded in this manner. The following locking circuit for-winding III of relay P2 is set up when this relay is energized: earth, winding II of relay F2,,wind ing III of relay P2, contacts 111 03, 100712, winding of rotary magnet'Dm, battery, earth. The rotary magnet Dm is not energized in this circuit but relay F2 is reenergized, in addition to relay P2. Relay F2 closes its contacts 71]2 and 72;2 which causes earth to be applied direct to the c-lead over these contacts and over contact 69112 for the purpose of guarding against another toll connection. ,In order to call the sub: scriber the operator again-throws over the-key FT. This causes relay B2 in the final selector LW2 to be energized as described above. The following circuit for relay R2 is then'completedz earth, contact 119- 92, windingllof elay R2, contact 109322, winding of rotary magnet Dm, battery, earth. The rotary magnet is not energized in this circ it. Relay R2 applies ringing current to thespeaking leads over the following route: earth, ringing current source of supply RQ, contact cs2, winding I .of relay Y2, contact 57 02, b-wiper of thefinal selector, LWZ, contacts 58p2, 52312,. battery, earth. The winding. II of relay Y2 is short-circuited by contact 6372 during the ringing current transmission. When the subscriber lifts his receiver a direct current cir.

cuit is closed in which relay y2 is energiz Relay Y2 closes its contact 52; 2 and th switches through the Zr-133d. and places Winding I of relay A2 in the direct current circuit tending over the subscribers loop. Relay A2 is energized and switches through the b-lead due to the actuation of its contact 56a2 Relay is disconnected from the b-lead by the opening of contact 6ly2 so that the transmission, of ringing current is discontinued. The two speaking leads are thus switched through after relay R2 has been released. 7

If the subscriber is engaged in a local call,

relay Pa -after the energization of relay P3, can.

not be energized due to the parallel connected lowresistance winding I of relay P2 of the other finalselector set to the same subscribers line. Due to contacts 591.23 and 60103 being closed the toll operator at the position FF is able to speak to the subscriber T12. engaged in a local call and I to advise him or" the arriving toll call and, at the same time, request him to cut off the local connection.

afresh and causes relay B2 in the final selector LWZ to be reenergized. This causes earthto be applied to th'e alead of the final selector LW2 in the following circuit since the relay F2 If the subscriber does not complywith the operators request she depresses the key FT has been released due to the energization of,

associated with the other final selector is short-.

circuited and thus caused to release due to earth being applied to the a-lead. The release of relay Y2 causes the o-lead to be cut off at contact 511/2 so that relay A2 also releases. This short-circuits winding I of relay P2, energized in local connection, due to the releasing contact 57412 and the closed contact 7002'. Relay P2 of the final selector releases and opens its contact 9102 so that the called subscriber Tn will be disengaged. Relay P2 of the final selector LW2 is now able to operate. j

The further switchingoperations have already been described above.

Whengafter the end of the conversation, the

subscriber replaces his receiver, the two feeding bridge relays Y2and A2 of the final selector LW2 are released. The final selector, however, i not" yet released and, moreover, the clearing signal is first transmitted to the toll position FTP by the following circuit for relay S in the repeater Ue being set uponthe release of relay Y21: earth, winding I of relay- B2, contact-6M2, junction line VL, b-wiper of the toll group selector FGWl, contact 41101, lower secondary winding of therepeater Ue, contact 2912, winding of relays, battery, earth. This causes the follow ing circuit for relay S2 at the toll position FP to be closed: earth, contacts35s, 34yywinding of relay B, lower primary winding of the repeater Us, o-lead, jack Kl, plug St, Winding of "relay SZ, plug St, jack Kl, a-lead', upper primary winding of the repeater Ue, Winding of relay A, battery, earth: Relays A and B are not energize'din this circuitbut relay SZ at the toll posi- FGWl is cut on, causing relay C1 to The test circuit to the final selector When the operator new.

26c, the test circuit to the toll group" If, on the other hand, the

LWZ is cutoff when contact 42cl in the group I selector FGWlis opened. Relay P1 in the toll group selector FGWI is released and initiates the general release in known manner.

Relay C2 in the final selector LW2 is now released and by opening contact 9503 breaks the locking circuit for winding II of relay P3. This relay relapses and by means of contact 111123 cuts off the locking circuit for relays P2 and F2. The following circuit for the rotary magnet Dm is completed when relay P2 is released: earth, off-normal contact 108k2, contacts 10702, 10202,.103112, 101122 winding of rotary magnet Dm, battery, earth. Contacts 105112 and 106112 are closed on .the energization of rotary magnet Dm. This completes the following circuit for relay U2: earth, contacts 108k2, 107122, 106d2, 105d2, windingII of relay U2, battery, earth. Relay U2 is energized and opens its contact 103112. The circuit for the rotary magnet Dm is thus cut off. The rotary magnet Dm releases and in turn reopens contacts 106d2 and 105112. Relay U2 is deenergized and recloses the circuit for the rotary magnet. Relay U2 and the rotary magnet Dm thus interact in the manner described above after the manner of a relay interrupter and advances the switch step by step to its original position in which the off-normal contact 108122 is opened and the switch is finally brought to rest. The locking circuit for relay P3 is cut off on the release of relay C2 due to the opening of contact 9503. I

The switching operations in the final selector LW2 in the case of a local call will now be briefly explained. A local call is characterized by the absence of the additional impulse between the two impulse series for the setting of the final selector. Therefore, relays B2, F2, and P3 cannot be energized. At the end of the impulse series for this setting operation the following test circuit is. closed during the release period of relay U2: earth, contacts 95:23, 92123, b2, 89;2, 85a2, 83u2, 82u2, 81r2, 76192, windings II and I of relay P2, c-wiper of the final selector LW2,

battery, earth, in the subscribers Tn preselector. If the subscribers line is idle, relay P2 is energized and switches through the two speaking leads as described above. The high resistance winding II is short-circuited bythe closing of contact 69p2 and the seized line is guarded against other seizures in known manner. The circuit for the rotary magnet Dm is opened by the opening of contact 101122. The following circuit for the ringing relay R2 is closed when, during the release period of relay U2, contact 100112 is closed: earth, interrupter LU, contacts 11'7u2, 118122, winding II of relay R2, contact 100112, winding of rotary magnet Dm, battery, earth. The rotary magnet Dm is not energized in this circuit. 'Ringing current is now applied in the manner described in connection with a toll call. If relay U2 has been released, relay R2 is energized in the following circuit for the repeat call: earth, time switch SS, winding I of relay R2, contacts 114v2, 99122, 100p2, winding of rotary magnet Dm, battery, earth. The rotary magnet is not energized in this circuit. If the subscriber lifts his receiver in a ringing pause, the energizing circuit for relay Y2 extends as follows: earth, contact 6212, windings II and I of relay Y2, contact 57392, b-wiper-of the final selector, LW2, subscribers line loop, a-wiper of the final selector LW2, contacts 58102, 521 2, battery, earthv Relay Y2 is energized and in addition to causing the switching operations described in connection with the setting up of a toll call breaks the circuit for the ringing relay R2, controlled over the interrupter LU, due to the opening of contact 116y2. Contact 1151/2,

at the same time, closes the following circuit for relay V2; earth, winding II of relay V2, contacts 115y2, 118b2, winding II of relay R2, contact 10Qp2, winding of rotary magnet Dm, battery, earth. The rotary magnet Dm is not energized in this circuit. Relay V2, by the opening of contact 114122, cuts off the circuit for the ringing relay R2 controlled by the time switch SS. In addition it is placed in a locking circuit over contacts 11312 and 99172 independent of relay Y2.

The final selector is released when the calling and called subscribers replace their receivers. This causes relay C2 to release and, in addition, causes the release of the two feeding bridge relays Y2 and A2. Winding I of the test relay P2 is short-circuited over contacts 6802 and 67112. Relay P2 restores and causes the release of the final selector in the same manner as that applied in the case of a toll call.

Finally, the case will be considered in which the called subscriber Tn has not replaced his receiver at the end of the toll call, while the toll operator at the position FP withdraws the plug St from the jack K1. Relays C2 and P3 in the final selector LW2 are released in the manner already described. P3 opens its contact 111123 and thereby cuts off the locking circuit for winding III of relay P2 and winding II of relay F2. Relay F2 is then released but the slow-acting relay P2 still remains energized even after the short circuit for its winding I has been removed in the following circuit due to the opening of contacts '71 f2 and 72 2: earth, contact 69122,

winding I, c-wiper of the final selector LW2,

battery, earth in the subscribers preselector. The subscriber Tn is, therefore, no longer engaged in a toll connection due to the fact that the earth applied direct to the c-lead is disconnected by the release of relay F2. 0n the other hand, due to the low resistance winding I of the test r lay P2 being connected to the c-lead his line is guarded in known manner against an incoming local call. I-Iis line, therefore, may be seized afresh for an additional toll call even if he has not replaced his receiver.

What is claimed is: r

1. In a telephone system in which low value and high value connections are extended to called lines over the same connecting devices, means responsive to a connection for guarding a line against subsequent connections of one or both values depending on the value of the first connection; and means responsive to the release of the calling party from a high value connection prior to the releaseof the called party therefrom for changing the line guarding to correspond with that of low value connections.

2. In a telephone system in which low value and high value connections are extended to called lines over the same connecting devices, means effective in a low value connection for guarding a line ,against subsequent low value connections, means effective in a high value connection for guarding a line against subsequent connections of either high or low values, and means responsive to the release of the calling party from a high value connection prior to the release of the called party therefrom for removing the guard against subsequent high value connections without releasing the connecting devices involved in the first connection.

3. In a telephone system, an automatic switch,

a called line, means for operating the switch to extend a connection of either of two classes to the line, means effective in a connection of one class for guarding the line against a subsequent connection of that class, means effective in a connection of the other classfor guarding the line against subsequent connections of either class, and means controlled jointly by the calling and called parties involved in a connection of said other class for removing the guard againstconnections of the other class while maintaining the guard against connections of said one class.

4. In a telephone system, an automatic switch,

a called line, means for operating the switch to extend a connection'of either of two classes to the line, means effective in a connection of one class for guarding the line against a subsequent connection of that class while, permitting subsequent connections of the other class, means effective in connections of the other class for guarding the line against subsequent connections of either class, and means responsive to the calling party releasing from a connection of said other class prior to the release of the called party therefrom for removing the guardagainst subsequent connections of said other class while maintaining the guard against subsequent connections of said one class.

5. A telephone system as claimed in claim 1 in which the change in the guarding of a line upon the release of a calling party from a high value connection is brought about by the release of relays in the connecting device which are operated only in high value connections.

6. In a telephone system, a combination local. and toll connector, means for operating the con-- nector to extend either a local connection ora toll connection to a called line, means effective in local connections for busying the called line against subsequent local connections, means controlled by the called party for maintaining the connector operated after the calling party releases from a toll connection, and means in the connector effective when the same is held by the called party for guarding the line against. subsequent local connections only.

FRIEDRICH LILL. 

